Key witnesses were also instructed by federal prosecutors and agents to preserve all documents and emails relating to Zimmer's allegations, sources told NBC in the report.

Federal agents have questioned Zimmer chief of staff Dan Bryan and communications director Juan Melli — two of at least five witnesses Zimmer told the FBI could confirm that she had informed them about a conversation she said she had with Lt. Gov. Kim Guadagno in May, the report said.

Key witnesses were also instructed by federal prosecutors and agents to preserve all documents and emails relating to Zimmer's allegations, sources told NBC in the report.

Federal agents have questioned Zimmer chief of staff Dan Bryan and communications director Juan Melli — two of at least five witnesses Zimmer told the FBI could confirm that she had informed them about a conversation she said she had with Lt. Gov. Kim Guadagno in May, the report said.